Peruvian Booby

The Peruvian booby (Sula variegata) is a seabird with a striking contrast in plumage. Its upperparts are a rich brown, while the underparts, including the head, are a pristine white. The wings are adorned with white mottling, and the wing-coverts are tipped with white, creating a distinctive scale-like appearance. The bill is long, pointed, and grey, complementing their grey webbed feet, which stand in contrast to the vibrant hues of their blue-footed and red-footed relatives.

Identification Tips

When identifying the Peruvian booby, look for the larger size in females, who are on average 19% heavier and possess wings that are 4% larger than males. The sexual dimorphism is subtle but noticeable to the discerning eye.

Habitat

This species is intimately tied to the Humboldt current, favoring the cool, nutrient-rich waters off the South American coast. They are most commonly found on the Peruvian coast and extend southward to central Chile.

Distribution

The Peruvian booby is endemic to the Peruvian current and is less widespread than other booby species. It is the most populous seabird along the Peruvian coast and is a significant contributor to the region's guano production.

Behaviour

Peruvian boobies are known for their nesting habits on smooth, windswept sand flats, which provide the ideal temperature range for their nests. They are plunge divers, foraging close to shore and often in groups, with dives typically lasting between 3.1 and 3.4 seconds.

Song & Calls

Adult Peruvian boobies communicate with a variety of vocalizations. Females produce trumpet-like quacks and honks, while males emit a distinctive whistle. These vocalizations take years to develop and are unique to the species.

Breeding

Breeding occurs throughout the year, peaking in the austral spring-summer. Clutch sizes range from one to four eggs, with two to three being most common. Both parents share in incubation duties, which last around 4 to 5 weeks, and the rearing period extends to about 3 months. Breeding success is closely tied to food availability.

Similar Species

While there are no subspecies of the Peruvian booby, they can hybridize with the blue-footed booby, resulting in offspring that are capable of reproduction.

Diet and Feeding

The Peruvian booby's diet is primarily composed of anchovy, especially the Peruvian anchoveta, supplemented by mackerel depending on prey abundance. Their reliance on the Humboldt Current's upwelling system ensures a steady food supply, although El Niño events can disrupt this and affect breeding success.

Conservation status

The Peruvian booby is currently listed as Least Concern on the IUCN Red List, reflecting a stable population. However, environmental changes such as El Niño can have significant impacts on their food sources and breeding success.